The Droplet Merger Chip is a glass microfluidic device designed for the merging of droplets in the volume range 400 pl (Ø90 μm) to 900 pl (Ø120 μm). The budding mechanism used for reagent addition involves the generation of a stream of droplets at the first junction which pinch off droplets as they form at the second junction. This device is ideal for high throughput experimentation and performing assays inside droplets.